Adding a little to the information provided by D&RGW 223
The B&T was built in 1914 by a group of associates from the Salt Lake Hardware Company. The mine was operated by the American Fuel Company.
The D&RG operated and maintained the line until 1925. As a result of financial difficulties the Chesterfield Coal Company acquired the American Fuel Company. At that time an agreement was reached whereby the D&RGW operated the track and the coal company was responsible for maintenance.
According to a 1912 map there was a wye at Thompson, just east of the stock yards. The B&T constructed their line from the wye to the mine at Neslen, later named Sego.
It appears that the majority of the coal output was purchased by the Rio Grande.
Jimmy